By faaar the most important condition for a C/R bluff is if the turn went check/check

C/R for value is more of a function of accurately assessing your opponent's hand range- for instance, say action goes

BTN raises HERO calls in BB with 55
flop Ac 8d 5s
check/3/4 pot/call (we for sure raise here sometimes but a call is definitely fine a fairly large % of the time)
turn 2 check/check
river A- anything but a checkraise is very bad unless we thinkg our villain is going to raise with any ace and call a 3bet